Past Paper Mistakes

Question 1

How does a catalyst work?

Answer 1

A catalyst provides an alternative pathway with a lower activation energy

Question 2

How to obtain pure water from sea water

Answer 2

Simple distillation

Question 3

Chemical name of compound when iron rusts

Answer 3

Iron (III) oxide / (Fe2O3)

Question 4

Metal used to galvanise iron

Answer 4

Zinc

Question 5

Test for hydrogen

Answer 5

Squeaky pop with lighted splint

Question 6

Observations when lithium reacts with water

Answer 6

• Fizzing/Effervescence
• Moves across the surface
• Lithium becomes smaller as it dissolves

Question 7

Ionic bonding definition

Answer 7

A type of bonding that involves the electrostatic attraction between oppositely charged ions

Question 8

Reason for stirring water (molar enthalpy change)

Answer 8

To allow the heat energy to be distributed evenly

Question 9

Prove it is pure water

Answer 9

Heat the water to measure the boiling point. If it boils at 100 degree celsius, it is pure water

Question 10

Lower temperature (collision theory)

Answer 10

As temperature decreases, the average kinetic energy of the particles decreases, so there are less frequent successful collisions, therefore the rate of reaction is slower